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Related papers: Global Thermal Instability in the Spherical Inters…

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We study, by means of adaptive mesh refinement hydro- and magnetohydrodynamical simulations that cover a wide range of scales (from kpc to sub-parsec), the dimension of the most dissipative structures and the injection scale of the…

Astrophysics · Physics 2009-11-13 Miguel A. de Avillez , Dieter Breitschwerdt

We simulate fragmentation and gravitational collapse of cold, magnetized molecular clouds. We explore the nonlinear development of an instability mediated by ambipolar diffusion, in which the collapse rate is intermediate to fast…

Astrophysics · Physics 2009-10-31 R. Indebetouw , E. G. Zweibel

Turbulence is thought to be a primary driving force behind the early stages of star formation. In this framework large, self gravitating, turbulent clouds fragment into smaller clouds which in turn fragment into even smaller ones. At the…

Solar and Stellar Astrophysics · Physics 2016-03-17 David Guszejnov , Philip F. Hopkins

Substellar atmospheres are observed to be irregularly variable for which the formation of dust clouds is the most promising candidate explanation. The atmospheric gas is convectively unstable and, last but not least, colliding convective…

Astrophysics · Physics 2007-05-23 Christiane Helling , Rupert Klein , Erwin Sedlmayr

This paper is a numerical study of the condensation of the warm neutral medium (WNM) into cold neutral medium (CNM) structures under the effect of turbulence and thermal instability. Using low resolution simulations we explored the impact…

Astrophysics of Galaxies · Physics 2014-07-09 E. Saury , M. -A. Miville-Deschênes , P. Hennebelle , E. Audit , W. Schmidt

The existence of substellar cold H2 globules in planetary nebulae and the mere existence of comets suggest that the physics of cold interstellar gas might be much richer than usually envisioned. We study the case of a cold gaseous medium in…

Astrophysics of Galaxies · Physics 2016-08-08 Andreas Füglistaler , Daniel Pfenniger

In this work, we explore the link between star formation, turbulence and the thermal state of the multi-phase ISM. We analyse a suite of stratified box simulations modelling a realistic ISM that aims to probe environments similar to those…

Tidal Downsizing (TD) is a recently developed planet formation theory that supplements the classical Gravitational disc Instability (GI) model with planet migration inward and tidal disruptions of GI fragments in the inner regions of the…

Earth and Planetary Astrophysics · Physics 2015-09-30 Sergei Nayakshin

The mechanisms that maintain turbulence in the interstellar medium (ISM) are still not identified. This work investigates how we can distinguish between two fundamental driving mechanisms: the accumulated effect of stellar feedback versus…

A theory of clustering of inertial particles advected by a turbulent velocity field caused by an instability of their spatial distribution is suggested. The reason for the clustering instability is a combined effect of the particles inertia…

Chaotic Dynamics · Physics 2007-05-23 Tov Elperin , Nathan Kleeorin , Victor S. L'vov , Igor Rogachevskii , Dmitry Sokoloff

Context: The gas density structure of the cold molecular phase of the interstellar medium is the main controller of star formation. Aims: A theoretical framework is proposed to describe the structural content of the density field in…

Fluid Dynamics · Physics 2023-08-15 Fabien Thiesset , Christoph Federrath

In a new simple model I reconcile two contradictory views on the factors that determine the rate at which molecular clouds form stars -- internal structure vs. external, environmental influences -- providing a unified picture for the…

Astrophysics of Galaxies · Physics 2016-02-17 Sharon E. Meidt

We discuss the temperature distribution in a two-dimensional, thermally unstable numerical simulation of the warm and cold gas in the Galactic disk, including the magnetic field, self-gravity, the Coriolis force, stellar energy injection…

Astrophysics · Physics 2009-11-06 A. Gazol , E. Vazquez-Semadeni , F. J. Sanchez-Salcedo , J. Scalo

We review recent advances in the analytical and numerical modeling of the star formation rate in molecular clouds and discuss the available observational constraints. We focus on molecular clouds as the fundamental star formation sites,…

Identifying the processes that determine the initial mass function of stars (IMF) is a fundamental problem in star formation theory. One of the major uncertainties is the exact chemical state of the star forming gas and its influence on the…

Models fail to reproduce observations of the coldest parts of the Sun's atmosphere, where interactions between multiple ionized and neutral species prevent an accurate MHD representation. This paper argues that a meter-scale electrostatic…

Solar and Stellar Astrophysics · Physics 2023-06-07 Samuel Evans , Meers Oppenheim , Juan Martínez-Sykora , Yakov Dimant , Richard Xiao

We present a method for modelling star-forming clouds that combines two different models of the thermal evolution of the interstellar medium (ISM). In the combined model, where the densities are low enough that at least some part of the…

Solar and Stellar Astrophysics · Physics 2015-03-19 Matthew R. Bate , Eric R. Keto

The Turing instability is a paradigmatic route to patterns formation in reaction-diffusion systems. Following a diffusion-driven instability, homogeneous fixed points can become unstable when subject to external perturbation. As a…

Pattern Formation and Solitons · Physics 2015-09-02 Joseph D. Challenger , Raffaella Burioni , Duccio Fanelli

We study the interplay among cooling, heating, conduction, and magnetic fields in gravitationally stratified plasmas using simplified, plane-parallel numerical simulations. Since the physical heating mechanism remains uncertain in massive…

Cosmology and Nongalactic Astrophysics · Physics 2012-12-05 Michael McCourt , Prateek Sharma , Eliot Quataert , Ian J. Parrish

One of the main mechanisms that could drive mass outflows on parsec scales in AGN is thermal driving. The same X-rays that ionize and heat the plasma are also expected to make it thermally unstable. Indeed, it has been proposed that the…

Astrophysics of Galaxies · Physics 2020-04-29 Randall Dannen , Daniel Proga , Tim Waters , Sergei Dyda